Procedures for ablation of persistent or long lasting atrial fibrillation are frequently long and require extensive ablation. Some electrophysiologists administer the drug ibutilide during these procedures to help organize the fibrillatory activity of the left atrium with the hope that this may shorten the length of the procedure and duration of ablation needed. Currently there is no standardized approach of administering the drug ibutilide during these procedures, thus the investigators cannot be certain that administering this drug does in fact facilitate the procedure. The aim of the MAGIC-AF Trial is to see if administering a standard dose of the drug ibutilide at a standard time in the procedure can allow for a reduction in the ablation procedure time. The investigators hypothesize that administering ibutilide during these procedures will result in a reduction in the procedure and ablation time required.